An emulsifiable concentrate (EC) is one of agrochemical formulations which have been most widely used since it has advantages in that it is easy to prepare and handle, and it may efficiently and economically deliver agrochemical active materials. The emulsifiable concentrate is prepared from oily active ingredients, or from active ingredients which may be dissolved in non-polar hydrocarbon solvents, for example, xylene, C9-C12 aromatic solvents, kerosene, or other proper solvents, and contains a surfactant to ensure excellent emulsion stability and spontaneous emulsification in spray tanks. However, the emulsifiable concentrate has a problem in that it is harmful to environments and human bodies since an excessive amount of a solvent is used in addition to the active materials of the agrochemicals and the surfactants.
To solve the above problems, formulations in which a solvent is used at a minimum amount and the other portion of the solvent is replaced with water have been developed. Such formulations include microemulsions (MEs), and oil-in-water emulsions (EWs). However, the formulations have problems in that they are more difficult to handle than solid formulations since they are in a liquid phase, and have poor stability which causes creaming, flocculation, ripening, and coalescence of the formulation since they are in a heterogeneous phase composed of water and oil. Also, the formulations have a problem in that a large amount of agrochemicals stick to the inner walls of containers upon packing in glass bottles or special synthetic resin containers, resulting in an increase in packaging costs.
To solve the above problems, Korean Patent No. 10-0432922 discloses a method which includes emulsifying an agrochemical active material in a minimum amount of a solvent and water and evaporating the water to obtain a solid emulsifiable concentrate. However, the method has problems in that the yield is low since the active material, the surfactant, and the like, which have a lower boiling point than the solvent or water, are evaporated during an evaporation process, and therefore it requires a special dryer which can be used to rapidly dry the active material at a temperature of 100° C. or less or lyophilize (cryosublimate) the active material, and it is difficult to prepare chemicals which severely break down at a high temperature.
Meanwhile, typical emulsifiable granules (EGs) or emulsifiable powders (EPs) include white granules having a particle diameter of 0.1 μm to 100 μm, and thus have a problem in that it is difficult to prepare a transparent microemulsion having a particle diameter of 0.001 μm to 1 μm (i.e., 1 nm to 1,000 nm) when the emulsifiable granules or powders are diluted in water.